Cubic boron nitride (cBN) has high hardness next to diamond and excellent heat conductivity, and has excellent merits as a tool material where it is low affinity to iron as compared to that of the diamond. In recent years, many investigations have been made on a cubic boron nitride sintered body having a cubic boron nitride content.
As a prior art of the cubic boron nitride sintered body having a high cubic boron nitride content, it has been known a cubic boron nitride sintered body in which the cubic boron nitride sintered body is constituted by 88 to 97% by volume of cubic boron nitride, and the remainder being a binder phase comprising at least one selected from a carbide, a nitride and a boride of W, Co and Al and a solid solution thereof and inevitable impurities, wherein the binder phase contains B6Co21W2, and when an X-ray diffraction intensity of the (420) plane of B6Co21W2 is made Iw, and an X-ray diffraction intensity of the (111) plane of the cubic boron nitride is made Ib, then, an intensity ratio Iw/Ib which shows a ratio of Iw to Ib becomes 0.10 to 0.40 (for example, see Patent Document 1).
It has also been known a cubic boron nitride molded material comprising polycrystalline lump of cubic boron nitride grains existing an amount of at least 70% by volume, and a binder phase which is qualitatively a metal (for example, see Patent Document 2).